Enterprises commonly maintain multiple copies of important data and expend large amounts of time and money to protect this data against losses due to disasters or catastrophes. In some storage systems, data is stored across numerous disks that are grouped together. These groups can be linked with arrays to form clusters having a large number of individual disks.
In cluster storage systems, data availability can be disrupted while arrays or groups of disks are being managed. For instance, it may be desirable to transfer access to disk groups from one array to another array. During this transfer, however, applications accessing data within the disk group can fail or timeout and cause a disruption to application service and operation of the enterprise. Such disruptions can also occur when arrays are added or removed from a cluster.
Regardless of the backup or data transfer techniques being used, enterprises can lose valuable time and money when storage arrays are taken offline or shutdown. In these situations, applications are shutdown, storage devices are disconnected and reconnected, LUNs (logical unit numbers) are re-mapped, etc. While the storage arrays are offline, operation of the enterprise is disrupted and jeopardized.